Re: 1) (elisp) `Advising Named Functions', 2) search filtering example

[Stefan Monnier]

>> If you do this, then you will break the callers, which expect the
>> value of this variable to be a single function.
> Tell that to the doc string for `add-hook', which has said what it
> says in this regard for a very long time.

There is no contradiction between the two.  `add-hook's doc talks about
the case where a "multiple-function hook" has a value which happens to
be a single function (which is an acceptable value for those hooks, for
historical reasons).

Whereas we're here talking about "single-function hooks", i.e. variables
which should only ever hold a single function and not a list of functions.
You can use (add-hook <hook> <function>) on them, just like you can use
(setq <hook> 5) on them.  That doesn't mean that it's correct to do so.


        Stefan